IMPROVEMENTS RELATING TO ROAD CUTTING APPARATUS

Abstract: A road cutting apparatus has a drum (38) for planing a strip in the road surface (46) as the apparatus moves in a working direction (56). To give the apparatus stability during cutting, the apparatus has three point suspension in that it stands on three wheels (26, 28, 30) at the apeces of a triangle ABC which is assymetric in relation to said direction (56) and the cutter drum (38) lies outside the triangle ABC adjacent one side AC and behind two of the wheels in said direction (56), so that the wheels can run on the uncut road surface as cutting takes place. The wheels at the ends of said triangle AC are independently steerable and the third wheel is a castor wheel giving the apparatus excellent manoeuvrability.

Description: Improvements Relating to Road Cutting Apparatus This invention relates to road cutting apparatus, and in particular concerns road cutting apparatus involving the removal and reinstatement of the road surface. With the requirement of for example repairing underground sewers, service pipes and the like, there frequently is the need to remove the road surface, and the road surface may be removed in a number of ways. For example it may be planed using typically a drum planer with cutting picks thereon. Road working may take place on the road surface and/or on pavements, and the road surface may be removed and replaced in a patching operation where an area of the surface is removed and is refilled by means of a replacement bituminous material such as a tarmacadam or asphalt. Patch work may be carried out where for example previous patch work has subsided or where the road surface has become worn or broken, and it is in this area indeed where considerable application for the utilisation of a road cutting apparatus presents itself. The road cutting apparatus should also be capable of mobility. Known are road cutting apparatus which are described as road grooving machines which are designed to roughen the surface of the road where wear has caused it to become smooth. An example of such a machine is shown and described in US Patent 2,311,891 dated 23rd February 1943. The machine described comprises a square frame carrying the road grooving discs and the frame is suspended at its corners by four wheels which are positionable between two positions namely a first position in which the wheels are aligned in the direction in which the machine moves as grooving takes place, and a second position at right angles to said direction so that the machine can move laterally to set the machine to perform a parallel grooving operation. Some of the support wheels must run on the newly grooved surface. Road grooving machines are different machines from the road planing machines or apparatus to which the present invention relates. European Patent Application No. 0067386 discloses a road planing machine which comprises two front support wheels and one rear support end traction wheel and two planing drums which are hung on the side of the machine. The machine is designed to move in a straight line and if it is maneouvered between cuts it must be done by different manual manipulation. The present invention seeks to address the removal of road surfaces in strips and by planing. In accordance with the present invention there is provided a road cutting apparatus comprising a frame, suspension and traction wheels, a rotary planer drum for cutting strips in the road surface, and means for raising the drum to a transport position, and lowering it to a cutting position, said drum being arranged in relation to said wheels such that the wheels run on the uncut road surface when the cutter is cutting a strip, characterised in that the wheels are steerable enabling the apparatus to be moved on the wheels and on the uncut road surface laterally of each cut strip after the drum has been placed in the raised position. It will be understood that reference to "wheel" does not necessarily mean that only a single wheel is present; it may be a wheel cluster involving two or more wheels. Preferably said wheels comprise first, second and third ground engaging and transport wheels arranged at the apices of a triangle in relation to the centroid of which the planer drum is offset, and wherein in side elevation in a direction transverse to the direction of cutting the first and second wheels lie to one side of the drum and the third wheel lies to the other side of the drum. By so arranging the wheels in relation to the drum so stable and effective cutting apparatus is provided. It is important that the drum should be offset in relation to the triangle defined by the suspension wheels because then the wheels run on the uncut surface of the road keeping the apparatus level. This is important as the apparatus is of substantial weight and is preferably a relatively small one man operated unit, on which the operator may be standing. The planer drum when operational produces torque reaction on the rest of the apparatus and as it is offset in relation to the said wheels there could be a tendancy for the apparatus to tip or rock about a side of the said triangle. The disposition and location of the three wheels in relation to the drum is of importance for optimum operation of the apparatus, having regard to the size of planing drum, the weight of the apparatus, the speed of cutting and the like, and in a preferred arrangement, as set forth hereinafter the said wheels are located at particular dispositions in relation to the drum. In a modified use of the apparatus the drum may be replaced by a slitting cutter or cutters for providing narrow cuts in the road surface. Preferably, the drum is arranged so that its centre is outside the said triangle defined by the three wheels. The apparatus may be adapted to be connected to a vehicle which provides the motive force for moving the apparatus over the ground. In such case, the apparatus preferably has a connection with the vehicle such that at least some of the vehicle weight can be transferred to the apparatus so that the drum will be thrust onto the ground with sufficient force for effective cutting by the drum. The traction may be provided by hydraulic driver means supplied with hydraulic fluid from the vehicle via the vehicle engine and a suitable pump means. Alternatively, the apparatus may be self propelled in which case it may be provided with its own engine connected to drive the planer drum and to provide the traction to the wheels for moving the apparatus. The transmission from the engine to the planer drum and traction wheel or wheels preferably is hydraulic and includes a pump and appropriate hydraulic motors. The traction wheel/wheels preferably is/are adapted to be driven at creep speed to give the planer drum sufficient time effectively to cut the road surface. The traction wheels are preferably also steering wheels, whilst the second wheel preferably is a castoring wheel. The third wheel may preferably be capable of manual angular adjustment to a number of positions, but once adjusted remains fixed until re-adjusted. The wheels may be relatively adjusted in height so that the drum can be set at an angle to the surface to be cut. Having regard to the above, it will be appreciated that as the apparatus with the planer drum in the lowered position, moves along the road surface so it will cut away a strip of road surface material. To one side of the strip the road surface, will remain uncut. As all of the wheels ride on the uncut road surface, then there is no undesirable tilting of the cutting apparatus due to its respective wheels running on different surface levels. The planer drum may be provided with a hood to embrace the cutter and to which suction may be applied for removing spoil and debris as described in our co-pending application No 9205346.1. The planer drum may be mounted for pivotal movement for height adjustment or it may be mounted for vertical sliding movement for such adjustment. The adjustment may be effected by means of a hydraulic ram or the like. The apparatus of the invention has the advantage that after the apparatus has made a cut in one direction, the steering wheels can be moved to a steered position in which their axes are parallel or substantially so and the apparatus can be moved sideways relative to the cut and then by further steering of the wheels rearwardly parallel to the cut so that a second parallel cut can be made, and the process can be repeated in order to remove an area of road surface. In the particular suitable arrangement, the steered wheels are also powered, by independent or coupled drive means, such as one or more hydraulic motors. Preferably, the first wheel is adapted to be steerable through a substantial angle in the order of 200°, whilst the third wheel (which can also be a depth control wheel) is adapted to be steered through an angle which is also substantial, and is in the order of 100° at least. An embodiment of the present invention will now be described, by way of example, with reference to the accompanying diagrammatic drawings, wherein;- Fig 1 shows a side view of a planer apparatus according to an embodiment of the invention; Fig 2 illustrates the rolling components of the apparatus shown in Fig 1, in perspective view; Fig 3 is a plan view of the rolling components of Fig 2 showing their spatial disposition; Fig 4 shows the cutting apparatus at the end of a movement in which a strip of road surface is removed; Fig 5 shows the apparatus in Fig. 4 with the first and second wheels in a steered position for moving the apparatus at right angles to the cutting direction; Fig 6 shows the apparatus in the Fig. 5 position but with the wheels steered to move the apparatus in the opposite direction to the cutting direction; Fig 7 shows the apparatus in the same condition as in Fig. 4 but during a subsequent cutting operation; and Fig 8 shows the apparatus with the steering wheels arranged to enable the apparatus to rotate substantially within its own dimensions in plan view. Referring to the drawings, the apparatus is illustrated by numeral 10 and is controlled by an operator 12 who controls the apparatus by means of control handle 14. In a modified arrangement of the apparatus, an operator 16 stands on an operator platform 18 (or seat) and travels with the apparatus, effecting control of same by means of a steering wheel 20 and a steering linkage 22. In one arrangement of the apparatus therefore the steering and control is by means of the handle 14, whilst in another arrangement the steering and control is by means of a steering wheel 20. The arrangement wherein the operator travels with the machine is preferred. The following further description of the machine applies to both arrangements. The machine comprises a main or spine plate 24 which in use is disposed vertically, and supported on the spine plate are first, second and third ground engaging and transport wheels 26,28 and 30 which ride on the road surface and support the machine. The first wheel 26 is a traction wheel and is connected to a hydraulic motor 32 by which the wheel 26 can be rotated at a creep speed to enable the appartus to move over the ground sufficiently slowly to enable effective planing to take place. Wheel 26, which may in fact be a pair of wheels arranged side by side, is mounted for steering movement on a king pin 34, and it is the king pin 34 which is connected to the steering handle 14 or to the steering transmission 22 so tha the wheel 26 can be infinitely variably steered and set to any angle within its range of angular setting. The second wheel 28 is a castoring wheel, that is to say it is mounted for rotation about a vertical axle 29 (Fig. 2) which is offset in relation to the centre of the wheel 28. The wheel 28 is laterally spaced relative to the wheel 26 as will be described, whilst the third wheel 30 is a support and depth control wheel. The wheel 30, as will be explained hereinafter is steerable and can be power steered in one embodiment or manually angularly adjusted and then fixed in adjusted position in another embodiment depending upon the manner in which the apparatus is to work. The spine plate 24 carries an internal combustion engine 36 which provides the motive power for propelling the apparatus, and also for power driving a planing drum 38 and for supplying hydraulic fluid to a control ram 40 the purpose of which is to height adjust the planing drum 38 by expansion and contraction of the ram. To this end, the planing drum 38 is carried by a housing or hood 42 which is pivotally mounted on the main plate at axle 44. Expansion and contraction of the ram 40 effects raising and lowering of the hood and planing drum 38 as a unit. The planing drum 38 is shown in Fig. 2 as penetrating the ground surface 46 (cutting position) and therefore is in its cutting mode, but it can be raised clear of the ground surface 46 as in Fig. 1 for transportation of the machine. The construction of the cutting drum, the function of the hood 42, the operation of the ram 40 and various other aspects of the drum 38 are described in more detail in International patent application No PCT/GB93/01944, to which reference is made for details. The spatial disposition of the support wheels 26,28 and 30 in relation to the cutter, is now explained with reference to Figs 2 and 3. In Fig 2 only the wheels 26, 28 and 30 and the planing drum 38 are shown, and this also applies to Fig 3, Fig 2 being a perspective view and Fig 3 being a plan view. Fig 2 also shows that the drum 38 which is rotating in the direction of arrow 56 is in the act of cutting a channel 52 in the road surface 46. The traction wheel 26 is being driven in the direction of arrow 54 in order to propel the machine in the direction of arrow 56. Optionally wheel 30 may be a traction wheel, and if it is, it is also driven in the same direction as wheel 26. Taking arrow 56 as the predetermined straight line direction in which the machine is designed to operate. the spatial dispostion of the wheels 26, 28 and 30 in relation to the drum 38 is as follows 1. In side elevation in relation to said direction 56 (which corresponds to the Fig 1 illustration) the first and second wheels 26 and 28 are to one side (leading) of the drum 38, whilst the third wheel 30 is to the other side (trailing) of the drum 38. Wheel 28 trails wheel 26. 2. As shown in Fig 3, the drum 38 is offset in relation to the triangle defined by lines 58, 60 and 62 which connect the centres of the wheels 26, 28 and 30 so that the centre of drum 38 is displaced from the centroid of that triangle. In fact as shown in Fig 3, the drum 38 is located with its centre outside the triangle. 3. In front view, looking in the direction of arrow 64 in Fig 3, the third wheel 30 is located between the first wheel 26 and the second wheel 28. By providing three wheels it is ensured that all wheel remain on the ground and the particular spatial disposition of the wheels is provided because the equipment is designed so that the drum 38 can cut a channel 52 in the surface 46 whilst the three support wheels 26, 28 and 30 remain on the uncut road surface, as shown in Fig 2. Thus, stable support is provided by the wheels whilst the offset cutter makes a deep cut in the road surface as shown. This is of advantage for maintaining the levelness of the machine, because it must be borne in mind that as the cutting drum 38 cuts the channel 52, there will be a torque reaction on the machine, and as that torque reaction is offset there could be a tendancy for the machine to rock about one of the sides 58, 60 or 62 of the triangle each of which is at an angle (other than 90°) to the direction of operation 56. This can be substantially avoided or nullified by designing the machine to keep the centre of gravity of the machine within the angle ABC shown in Fig. 3. The efficiency of the machine will depend on the positioning of the three wheels and the positioning of the cutter drum so that the centre of gravity lies as centrally of the triangle as possible. It is possible to vary the spatial arrangement of the wheels 26, 28 and 30 from that specifically illustrated in Fig 3, and if for example the traction wheel 26 is located immediately in front of and in alignment with the drum 38 some advantage can be provided. When it is offset as shown in Fig 3, it is desirable that the overlap in frontal elevation be preserved so that the torque reaction due to the drive wheel torque produces a down thrust upon the drum to improve cutting efficiency. Conversely, the torque reaction to the cutting drum increases the down force on the drive wheel thereby increasing tractive adhesion and effort. Particular advantage is obtained by making the second wheel 28 a castoring wheel, as wheel scrub can be eliminated. The apparatus, because it desirably has its centre of gravity in the triangle, may be provided with a floating ballast weight which can be moved either manually or by hydraulic force under the control of the operator such that the effective centre of gravity of the machine is biased by choice towards the cutting drum during cutting and towards the wheel 26 for increased tractive effort. Reference is now made to Figs. 4 to 8 to illustrate the exceptional maneouvrability and utility of the apparatus. Referring to these drawings, the detail of the apparatus has been omitted in the interests of clarity. Illustrated diagrammatically and in dotted lines are two steering rams 80 for the first wheel 26 and 82 for the third wheel. The said steering rams 80, 82 are coupled to the wheels 26 and 30 to enable the first wheel 26 to be steered through an angle of up to 200°, whilst ram 82 is connected to wheel 30 to enable it to be steered about an axis 83 through an angle of up to 110°. The steering arrangement is such that wheel 26 can be steered to 100° to either side of the position shown in Fig.4, whilst wheel 30 is adapted to be steered by 100° in an anti clockwise direction from the position shown in Fig. 4. The apparatus is shown in Fig. 4 as having completed a working stroke and after having travelled in the direction 56. The strip 52 has been cut in the road surface, and the apparatus has now stopped the cutting, forward motion. Next, the drum 38 is raised clear of the ground, and this is followed by steering movements of the wheels 26 and 30 to position them so that their axes are parallel or nearly so. The wheels 26 and 30 can be set to any angle (within their range of movement) relative to the direction 56 and such angle can be as low as 20-30°. Specifically, in Fig. 5 wheels 26 and 30 have been steered to positions at right angles to the positions shown in Fig. 1. The apparatus can now be moved upwards in Fig. 2 as indicated by arrow 88 so that it moves in a direction at right angles to the strip 52. It should be noted again that all wheels 26, 28 and 30 remain on the uncut surface of the road. In Fig. 5 the castor wheel 28 is shown as having swung about its castoring axis 90 into line with the direction 88 which it will do as soon as the apparatus moves in said direction 88. When the apparatus has been laterally displaced in the direction of arrow 88 to the position shown in Fig. 6, the wheels 26 and 30 are returned to the Fig. 1 position by the power steering arrangments, and now the apparatus can be traversed rearwardly as indicated by arrow 92 back to an initial position ready to make the next cut parallel to the cut 52. Again the castor wheel 28 is shown as having swung into line with the direction of arrow 92 which it will do automatically as soon as the apparatus starts to move in the direction of arrow 92. Fig. 7 shows the apparatus in the course of making a second cut 94 in the road surface parallel to and contiguous with the cut 52 thereby progressively to remove a patch of road surface. It will be noticed that the wheel assembly 26 still runs on the uncut surface of the road so that the apparatus will remain level. It is also mentioned that the cutter drum 38 at the beginning of the movement to make the cut 94 will be lowered onto the road surface, and of course the castor wheel 28 will pull into alignment with the direction of movement 56 as the apparatus moves to make the cut 94. All movements of the planer are by powering of the wheel 26, or wheels 26 and 30 by their drive motors, which together with the steering capability described leads to an extremely versatile arrangement. The combined effect is even further enhanced insofar as is shown in Fig. 8, the steering wheel assembly 26 and steering wheel assembly 30 can be arranged at different steering angles in order to provide circumstances in which the apparatus can be powering of the wheels 26, 30 in opposite directions more or less to turn within its own width which is excellent for confined space working. If only one wheel is driven, the machine can be rotated about the other wheel. As well as being power steerable, the wheel assemblies 26 and 30 or either of them may be adapted additionally or alternatively for manual steering as required. In one preferred modification, the wheel 30 is manually steerable to any of a selected number of steered positions in which the wheel 30 can be locked. In at least one of these positions, the apparatus will move at an angle to the strip 52 or be "crabbed" rearwards and sideways relative to the strip when moving between positions corresponding to the position shown in Figs. 5 and 6. A particularly effective arrangement is provided in a relatively small manipulable and manoeuvrable planing apparatus, which is one man operated. Regardless of the operator control provided, it is preferred that these controls have a "dead man" handle arrangement whereby if the operator who is operating the machine suffers an accident or for any reason releases his hold on the controls, the machine will automatically stop. Also in this connection it may be arranged such that when the cutting drum 38 is raised for transportation, the drive thereto will automatically be cut off. Such drive may for example be a hydraulic motor, and prefereably the cutting drum will be rotated at a speed in relation to the creep speed wheel in a ratio in the order of 15 to 1. A unique feature of the apparatus resides in not interconnecting any of the wheels and the configuration of the wheels can be independently operated which provides co¬ ordinated steering geometry around a common turning point enabling conventional right or left turns. Additionally however, the wheels can also be positioned into parallel axis geometry to allow lateral displacement of the machine at any angle up to 90° to the normal straight line cutting direction. This is possible because each wheel can be arranged at an angle to said direction either by operator control or by self disposition.

Claims: CLAIMS 1. A road cutting apparatus designed to have a predetermined diretction (56) of cutting and comprising a frame (24), three suspension and traction wheels (26, 28, 30) at the apices of a triangle (ABC) providing three point support for the apparatus, a rotary planer drum (38) for cutting strips in the road surface (46), and relative movement means (40) for positioning the drum relative to the wheels between a transport position and a cutting position, said drum (38) being arranged outside said trianlge ABC and two (26, 28) of said wheels precede the drum (38) in said direction such that the wheels run on the uncut road surface (46) when the cutter is cutting a strip in said direction (56), characterised in that the wheels are steerable enabling the apparatus to be moved on the wheels and on the uncut road surface laterally of said direction (56) after the drum has been placed in the raised position. 2. Apparatus according to Claim 1, characterised in that each of the sides AB, BC, CD of said trianlge lie at an angle to said direction (56). 3. Apparatus according to Claims 1 or 2, characterised in that the wheels (26, 28) are steerable so as to be disposable with their axes parallel to each other and at an angle to the said direction (56). 4. Apparatus according to any preceding Claim, characterised in that at least one of said wheels steerable. 5. Apparatus according to any preceding Claim, characterised in that each of two (26, 30) of said wheels is independently steerable, whereby the steerable wheels can be set for said lateral movement or rotation of the apparatus about a centre. 6. Apparatus according to Claim 4 or 5, characterised in that the steerable wheel or one of the steerable wheels is power steerable. 7. Apparatus according to any preceding Claim, characterised in that one (30) of the wheels is power steerable between two positions at right angles to each other. 8. Apparatus according to any preceding Claim, characterised in that one of the wheels is manually steerable. 9. Apparatus according to Claim 8, characterised by a tiller arm for steering said manually steerable wheel. 10. Apparatus according to Claim 9, characterised in that the tiller arm can be locked in any of a number of steering positions. 11. Apparatus according to any of Claims 2 to 11, characterised in that two of said wheels are traction wheels. 12. Apparatus according to any preceding claim, characterised in that one of the wheels is a castoring wheel (28). 13. Apparatus according to any preceding claim characterised in that the apparatus is controllable by an operator who walks beside the apparatus. 14. Apparatus according to any of Claims 1 to 12 characterised in that the apparatus is controllable by an operator who stands on an operator platform of the apparatus. 15. A road cutting apparatus designed to have a predetermined diretction (56) of cutting and comprising a frame (24), three suspension and traction wheels (26, 28, 30) at the apices of a triangle (ABC) providing three point support for the apparatus, a rotary planer drum (38) for cutting strips in the road surface (46), and relative movement means (40) for positioning the drum relative to the wheels between a transport position and a cutting position, said drum (38) being arranged adjustably on side AC of said trianlge ABC and two (26, 28) of said wheels precede the drum (38) in said direction such that the wheels run on the uncut road surface (46) when the cutter is cutting a strip in said direction (56), characterised in that the wheels are steerable enabling the apparatus to be moved on the wheels and on the uncut road surface laterally of said direction (56) after the drum has been placed in the raised position and the wheel (28) at the apex of the triangle (ABC) which is remote from said side (AC) is a castoring wheel (28). 16. A road cutting apparatus designed to have a predetermined diretction (56) of cutting and comprising a frame (24), three suspension and traction wheels (26, 28, 30) at the apices of a triangle (ABC) providing three point support for the apparatus, a rotary planer drum (38) for cutting strips in the road surface (46), and relative movement means (40) for positioning the drum relative to the wheels between a transport position, and a cutting position, characterised in that the wheels are steerable either (i) so that the wheels are parallel and enable the apparatus to be moved on the wheels laterally of said direction (56) or (ii) to enable the apparatus to be steered in a rotary or rotational path.

Inventors: LUPTON WILLIAM GEORGE, LUPTON, WILLIAM, GEORGE
Applicants: LUPTON WILLIAM GEORGE, ROTA PIC LTD, LUPTON, WILLIAM, GEORGE, ROTA-PIC LIMITED
Application year: 1994
Main classification: E01C23
IPC codes: E01C23